build(release): use native golang toolchain for official release builds (#37828)

Official releases are built by Golang toolchain with CGO disabled.

For packagers who need to cross-compile with CGO, use "build" target
with proper TAGS/LDFLAGS/CGO_CFLAGS to make "$(EXECUTABLE)" target run
the "go build" command.

By the way, drop i386 arch support

---------

Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

tools/build-release.sh

@@ -0,0 +1,72 @@
+#!/bin/bash
+set -euo pipefail
+
+GO="${GO:-go}"
+RELEASE_LDFLAGS="-s -w $LDFLAGS"
+RELEASE_TAGS="bindata $TAGS"
+RELEASE_PATH_PREFIX="${DIST}/binaries/gitea-${VERSION##*/}"
+
+RELEASE_PLATFORMS_DEFAULT=(
+  linux/amd64 linux/arm-5 linux/arm-6 linux/arm64 linux/riscv64 \
+  windows/amd64 windows/arm64 \
+  darwin/amd64 darwin/arm64 \
+  freebsd/amd64
+)
+
+RELEASE_PLATFORMS_GOGIT=(windows/amd64 windows/arm64)
+
+build() {
+  echo "building ${*} ..."
+  local target="${1:?}"
+  local variant="${2:-}"
+
+  local goos="${target%%/*}"
+  local goarch="${target##*/}"
+  local goarm=""
+  if [[ "$goarch" == arm-* ]]; then
+    goarm="${goarch#arm-}"
+    goarch="arm"
+  fi
+
+  local tags="${RELEASE_TAGS}"
+  local suffix
+  if [[ "$variant" == "gogit" ]]; then
+    tags="gogit${tags:+ ${tags}}"
+    suffix="-gogit-${target//\//-}"
+  else
+    suffix="-${target//\//-}"
+  fi
+
+  local output="${RELEASE_PATH_PREFIX}${suffix}"
+  local args=()
+  if [[ "$goos" == "windows" ]]; then
+    output="${output}.exe"
+  fi
+  args+=(-tags "$tags")
+  args+=(-ldflags "$RELEASE_LDFLAGS")
+  echo "  args: ${args[*]}"
+  echo "  output: ${output}"
+  # must disable CGO (host compiler & linker) to get host-independent static builds
+  CGO_ENABLED=0 GOOS="$goos" GOARCH="$goarch" GOARM="$goarm" "$GO" build "${args[@]}" -o "$output" .
+}
+
+main() {
+  # When building release binaries, some TAGS (bindata) are needed by the release script,
+  # so here it needs to use the TAGS to generate the assets (embed bindata).
+  echo "generating assets with tags=${RELEASE_TAGS}"
+  "$GO" generate -tags "${RELEASE_TAGS}" ./...
+  local platform="${1:-}"
+  for target in "${RELEASE_PLATFORMS_DEFAULT[@]}"; do
+    if [[ -z "$platform" || "$target" == "$platform/"* ]]; then
+      build "$target"
+    fi
+  done
+
+  for target in "${RELEASE_PLATFORMS_GOGIT[@]}"; do
+    if [[ -z "$platform" || "$target" == "$platform/"* ]]; then
+      build "$target" "gogit"
+    fi
+  done
+}
+
+main "$@"